Infections of mosquitoes with dengue viruses. The relative vector potential of several species of the Aedes scutellaris group of mosquitoes is being compared with that of Aedes albopictus and A. aegypti. The mosquitoes are infected by allowing them to ingest suspensions of the viruses. These suspensions are prepared by trituration and centrifugation of pools of A. aegypti previously infected by parenteral injection. Following a suitable incubation period, the mosquitoes are sealed in ampoules, quick-frozen, packed in dry ice, and sent to Dr. Leon Rosen's Laboratory in Honolulu for bioassay. Genetic relationships of mosquitoes of the Aedes scutellaris group. All cross breeding combinations between Aedes polyensiensis A. pseudoscutellaris, A. s. malayensis, A. (?) cooki, "Tafahi", and Niuafo'oa" have been attempted, but some are to be repeated for additional data. Some crosses have resulted in non-reciprocal fertility, and experiments are being planned to establish the possible existence of cytoplasmic factors that are responsible for this phenomenon. There are morphological characters by which the parental populations can be recognized, and the F1, F2, and backcross progenies are being examined to determine the mechanism of inheritance of these characters. A. (?) cooki, "Tafahi", and "Niuafo'oa" are autogenous, and attempts also are being made to determine the genetics of inheritance of this character in progenies of "Tafahi" and A. pseudoscutellaris.